Comparison of the metabolism of baicalin in rats orally administered with Radix scutellariae extract and Shuang-Huang-Lian extract

Shuang-Huang-Lian (SHL) is a traditional Chinese formula containing Flos lonicerae, Radix scutellariae (RS) and Fructus forsythiae, and is commonly used for treating acute upper respiratory tract infection, acute bronchitis and light pneumonia. The aim of the present study is to compare the metabolites of baicalin in rats when orally administered with SHL and Radix scutellariae, and try to explore the principle of SHL compatibility. By using LC-MS(n) and HPLC-DAD, the metabolites of baicalin were analyzed from bile, urine and feces of rats dosed with SHL and RS. Our results showed significant difference of baicalin metabolism between RS and SHL. However, baicalein was found to be the main metabolites of baicalin in intestinal tract after oral administration of RS and SHL, glucuronide, glucoside and methylated products were also found in rat urine after administration of either RS or SHL. Meanwhile, several sulphates were found in rat urine after RS administration, but not found after SHL. Among the metabolites of the SHL, potentially there existed a isomerized baicalin and methylated product: 5,7-dihydroxy-6-methoxyisoflavone-7-O-beta-glucopyranuronoside, but without unidentified metabolite M3. Baicalein-6-O-beta-glucopyranuronoside-7-O-beta-glucopyranuronoside and baicalein-6-O-beta-glucose-7-O-beta-glucopyranuronoside were first reported by this study. The major metabolites of baicalin of RS and SHL in rat bile were the same, including baicalin-6-O-beta-glucopyranuronoside-7-O-beta-glucopyranuronoside, baicalin-6-beta-glucopyranuronoside and 6-O-methyl-baicalin-7-O-beta-glucopyranuronoside. Moreover, baicalein-6-O-beta-glucose-7-O-beta-glucopyranuronoside was also first found in rat bile by this study. Although baicalin-6-O-sulfate-7-O-beta-glucopyranuronoside was found in rat bile after RS administration, no sulphated products were found after oral administration of SHL. These differences of baicalin metabolism between RS and SHL indicated that compatibility of medicines could result in the differences of metabolites.     

三层流体系统非线性界面内波传播理论的研究

基于波陡很小的假设, 利用摄动法, 讨论了任意深度的二维不可压缩、无黏性、无旋的三层流体系统. 在刚性上边界、平底不可渗透条件下, 给出了界面内波传播的统一理论以及描述其波剖面的近似非线性演化方程(NEEs). 最后讨论了几种特殊情形下的近似NEEs.结果表明文献导出的理论结果为本文的特殊情形.     

溶剂浮选分离富集雪莲中的黄酮

采用溶剂浮选法分离富集雪莲提取液中黄酮类化合物.考察了浮选溶剂、氮气流速、试液pH、浮选时间及电解质NaC1等因素对浮选效率的影响,优选出最佳浮选条件;对最佳条件下的浮选结果进行了评价,并与溶剂萃取法进行了对照.结果表明:前者明显优于后者.     

Micro-FTIR study on structure of macerals from Jurassic coals in Northwestern China

Jurassic coal in Northwest China is rich in resources and it is a necessary premise to reveal the chemical structure characteristics of the coal macerals in this region before the coal is put into reasonable and efficient use. Micro-FTIR technique was used to investigate the chemical composition and structures of vitrinite semifusinite and fusinite from Jurassic coal in Northwestern China. The results show that vitrinite and semifusinite have more aliphatic hydrogen, but fusinite has more aromatic hydrogen and C=O structure. The aliphatic hydrogen in semifusinite is higher than that in fusinite and it is this structure characteristic of semifusinite that led to the richer inertinite but higher reactivity of the Northwestern China coal. Not only vitrinite but also semifusinite and fusinite with weaker reducibility have less aliphatic hydrogen and more C=O structures than those with stronger reducibility. The different intensity of oxidation in the process of coalification is one of the causes that led to different type of reducibility.     

Efficient Regioselective Synthesis of the Crotonyl Polydatin Prodrug by <Emphasis Type="Italic">Thermomyces lanuginosus</Emphasis> Lipase: a Kinetics Study in Eco-friendly 2-Methyltetrahydrofuran

Bio-based solvents have recently been discussed as sustainable green and promising alternatives to conventional organic media for enzymatic processes. In this paper, highly regioselective synthesis of the 6″-O-crotonyl-polydatin catalyzed by Thermomyces lanuginosus lipase (TLL) in biomass-derived 2-methyltetrahydrofuran (2-MeTHF) was successfully performed for the first time. The results indicated that TLL lipase displayed significantly improved catalytic performance in 2-MeTHF than in other traditional solvents. Under the optimal conditions, the initial reaction rate, 6″-regioselectivity, and maximum substrate conversion were as high as 12.38 mM h^?1, 100 %, and 100 %, respectively. Moreover, further investigations on the operational stability, kinetic parameters like V _max, K _m, V _max/K _m, and E _a revealed that 2-MeTHF exhibited excellent biocompatibility and rendered the greener process of the enzymatic acylation.     

Proton-Calcium Scattering at Tp=200 Mev in the α-Particle Model

Elastic proton-⁴⁰Ca scattering at T_p = 200 MeV is calculated within the Glauber theory on the basis of the α-particle model. The results are compared with the experimental data and those calculated in the relativistic model.     

光谱电化学研究α-巯基苯并噻唑对铜的缓蚀机理

我们运用现场光谱电化学方法研究了α-巯基苯并噻唑对铜的缓蚀机理。研究表明α-巯基苯并噻唑是通过在金属铜表面形成一层致密的非水溶性配合物膜Cu^Ⅰ-MBT而起缓蚀作用的。     

高质量CdTe量子点的水相快速合成

系统考察了水相合成CdTe量子点的主要影响因素, 通过改变无水乙醇-水体系的体积, 提高NaHTe的合成质量, 并调整反应温度, 改变反应的初始pH值, 在水相中快速合成了量子产率高、粒径分布范围窄的CdTe量子点, 实现了对量子点发光性质的调控, 在最佳条件(无水乙醇3 mL, 水1 mL, 反应初始pH 8.0, 反应温度40 ℃)下, 最高量子产率达68%. 量子点胶体溶液在回流过程中有时产生白色沉淀, 放置7 d后, 未过滤白色沉淀的量子点比过滤后的量子点荧光强度提高15%, 白色沉淀还有减小粒径分布的作用.     

Study of fluorescence characteristics of the charge-transfer reaction of quinolone agents with bromanil

A spectrofluorimetric method was discussed for the determination of three antibacterial quinolone derivatives, ofloxacin (OFL), norfloxacin (NOR) and ciprofloxacin (CIP) through charge-transfer complexation (CTC) with 2,3,5,6-tetrabromo-1,4-benzoquinone (bromanil, TBBQ). The method was based on the reaction of these drugs as n-electron donors with the pi-acceptor TBBQ. TBBQ was found to react with these drugs to produce a kind of yellow complexes and the fluorescence intensities of the complexes were enhanced by 29-36 times more than those of the corresponding monomers. UV-vis, (1)H NMR and XPS techniques were used to study the complexes formed. The various experimental parameters affecting the fluorescence intensity were studied and optimized. Under optimal reaction conditions, the rectilinear calibration graphs were obtained in the concentration range of 0.021-2.42 microg mL(-1), 0.017-2.63 microg mL(-1) and 0.019-2.14 microg mL(-1) for OFL, NOR and CIP, respectively. The methods developed were applied successfully to the determination of the subject drugs in their pharmaceutical dosage forms with good precision and accuracy compared to official and reported methods as revealed by t- and F-tests.     

单壁碳纳米角的氧化、修饰及分散性

研究了影响单壁碳纳米角(SWNHs)分散性的因素, 并初步探讨了其分散机制, 通过氧化及表面修饰等方法增强了SWNHs在水和盐溶液中的分散性. 考察了溶液酸碱度和电解质浓度对SWNHs在水中的分散性以及吐温80对SWNHs在磷酸盐缓冲液(PBS)中的分散性的影响. 结果表明, pH值为6~10时, SWNHs分散良好; 电解质浓度越大, SWNHs的分散性越差; 吐温80能有效改善SWNHs在PBS中的分散性. 比较了3种SWNHs的氧化方法, 红外光谱、 X射线光电子能谱、 透射电镜、 粒度分析及Zeta电位分析结果表明, 氙灯催化过氧化氢氧化SWNHs的方法可引入大量含氧官能团, 显著提高了SWNHs在水中的分散性. 选择两亲性和生物相容性极好的羧基化磷脂聚乙二醇(DSPE-PEG-COOH)修饰氧化处理后的碳纳米角(SWNHox), 并从分散稳定性和Zeta电位两个方面进行了表征, 发现用DSPE-PEG-COOH修饰的SWNHox在PBS中的分散性良好. 该研究为SWNHs应用于药物转运和生物传感奠定了实验基础.